Since the introduction of the 300-mm wafer semiconductor material, Front Opening Unified Pods, or “FOUPs,” have become the standard storage and transport method of substrates and similar materials. FOUPs have been used to isolate and hold silicon wafers for use in semiconductor production. Semiconductors, fundamental in the design of digital circuitry, microprocessors, and transistors, require these wafers to remain in as close to immaculate condition as storage units allow. Accordingly, FOUPs allow wafers to be transferred between other machines used in the processing and measurement of wafers.
Prior FOUPs generally serve to preserve wafers from the surrounding clean room environment. In conventional semiconductor projects, FOUPs allow wafers to enter the apparatus via a load port and front opening door. Often, robot handling mechanisms may place the wafers into the FOUP, where they are clamped in place by fins and held for later use. Yet FOUPs today are hampered by methods and system designs which may contaminate their contents, chafe wafers, and delay loading and unloading of substrate wafer contents as a result of multifarious construction. Thus, there may be a need for an invention that more efficiently and accurately accomplishes the desired tasks of FOUPs.
Current substrate storage devices allow contained wafers to be cleaned with undirected, pressurized liquids, gases, and/or other substances. Yet FOUPs have been deemed vulnerable to the haze effect, whereby these undirected substances may provide inadequate cleaning, unable to target unwanted particulate matter. Due to typical FOUP construction, individual substrates, contaminated or otherwise, may not be removed due to immovability in clamping apparatuses. Thus, it has become standard to replace FOUPs several times during wafer processing in a Front-End Factory. But the creation of an alternative device with streamlined or improved cleaning methods may present itself as a key tool in the semiconductor industry, saving both time and energy without the need for replacement at such a quick rate.
Recent, rapid advances in technology have necessitated the creation of new devices to cope with the increasing demand for pacing in economies of scale. Yet due to non-recurring engineering, or the one-time costs in research and development of products, and time to market concerns, it may be considered implausible to base new designs on existing devices. Accordingly, economies of scale may only be achieved in the semiconductor product industry with manufacturing orders and shipments in high volume. Further, because repair of completed products may be considered impractical, incorporation of reliability and flexibility at the production stage has become imperative. Substrate storage devices directly affect these values, as reliability of semiconductor products depend on assembly, use, and environmental conditions at these crucial stages. Thus, improvements in substrate storage devices are correlated with productivity of semiconductor manufacturing.
Currently marketed substrate storage devices are affected by a number of reliability issues, including but not limited to mechanical stress, dust contamination, pressures, and temperature vulnerability. Prior substrate storage systems may be equipped with fins with which to hold wafers in place. Such fins clamp the wafers, which may be 100-200 micrometers thin and vulnerable to friction from other surfaces, and cause unnecessary chafing along both surfaces of the substrate. Prior substrate storage devices, in multiple iterations being of varying levels, are subject to extreme levels of mechanical pressure loads and accelerate replacement times with multiple stress points along the conductive surfaces of the device, produced in multiple parts in multiple iterations. These prior devices have proven unsatisfactory for certain applications in that they contain unnecessary gaps as a result of construction methods and provide a rigid, inflexible structure which may exist in excessive sizes, decreasing packing capacities in material transport systems.
Issues with prior substrate storage devices are exacerbated with construction sizes of typical FOUPs, which may be produced in multiple stages of multiple parts, typically holding a maximum of 25 wafer of 300 mm wafer fabs and device heights of upwards of 330 mm. Recalling that high volume shipments are imperative, the size of these FOUPs hamper scaling efforts and diminish efficiency by requiring the construction of the storage FOUPs in steps and parts, especially if smaller sized containers may be created to contain the same volume of substrate. Thus, a substrate storage device which streamlines construction processes may increase efficiency of creation, storage and ease of replication in the manufacturing process.
Because preservation of held substrate wafer quality may be the primary goal of such storage devices, an improved substrate storage device must allow for cleaning of contents without sacrificing the structural integrity of the system or the wafers themselves. Innovative flexible applications, such as the ability to remove a single substrate stack or module may therefore grant improved stacking, removing, and tracking over current storage devices like FOUPs.
It may be therefore an object of this invention to provide a device which may be used for substrate or wafer containment, transportation, and holding in semiconductor manufacturing or like processes. Another object of the invention may be to provide a storage device of single piece design with single material utilizing a system of alternating substrates and supporting rest latches. Another object of the invention may be to provide controllable buffer storage purge options which may be directional laminar gaseous flows across the contained substrates. Another object of the invention may be to provide self-centering device capabilities and substrate orientation capabilities which may allow for replacement of substrate stacks and/or modules.